| 摘要 |
An inductive power transfer system for coupling a power source to a load across an air gap is provided, including a primary unit and a secondary unit separable from the primary unit and arranged to receive power inductively from the primary unit when placed proximate thereto. The system includes a multi stage comparator for monitoring operating conditions within the secondary unit and feedback loop for transmitting a feedback signal to the primary unit when predetermined operating conditions are detected within the secondary unit. The primary unit is arranged to operate in a low power mode where power is applied to the primary winding for a minimal period during each switching cycle when no feedback signal is received and a high power mode where power is applied to the primary winding for the majority of each switching cycle when a feedback signal is received. The power transfer system functions by applying bursts of power from the primary to the secondary unit, the bursts becoming more frequent and of longer duration as the load on the secondary unit increases or the air gap increases, so as to transfer more power or maintain power as air gap losses increase. The bursts of power will also change their duration and frequency in correspondence with variations of the input power supply to the primary unit, so as to maintain the voltage regulation of the power delivered to the secondary unit. |
